Mold assembly

ABSTRACT

Injection blow molding equipment for the production of hollow articles wherein cores are axially inserted in blow molds and blank molds is disclosed. Compact core assemblies and fluid supply systems integral with the platens allow the mold parts to be mounted on the surfaces of opposed, relatively movable platens. Partible neck rings associated with each core open divergently outwardly as the blow mold and core separate, to shorten machine cycle time. A manifold, supplied with cooling fluid from the periphery of a core mounting plate, distributes heat transfer fluid to the core assemblies for cooling the neck rings. In one embodiment, mating blow mold sections are mounted on contra-oscillatable mounting members and are opened and closed by arcuate movement of the mounting members.

RELATED U.S. APPLICATION

This application is a continuation of our co-pending application Ser.No. 312,257, filed Dec. 5, 1972, now U.S. Pat. No. 3,941,539.

This invention relates to blow molding apparatus and methods forproducing hollow containers from softened plastic materials andparticularly relates to improved designs and methods of operation forinjection blow molding machines.

Certain injection blow molding machine designs have been proposedwherein core assemblies having associated split neck molds arealternately inserted axially into preform injection molds and blow moldsto form finished articles. In some of these designs, divergently openingblow mold parts are utilized so that upon separation of relativelymovable platens, the blow mold parts open divergently outwardly, therebyallowing removal of the blown article from the blow mold on theretracting core - the partible neck ring sections being maintainedclosed about the neck of the blown article. When the platens are fullyseparated, the finished articles must be removed from the cores. In someof these designs, neck ring parts, which open divergently outwardly, areutilized and these neck ring parts must be opened to allow a stripperring or other stripping means, for example, a blast of compressed air,to remove the finished article from the core. These designs aredisadvantageous because of the requirement for complicated blow moldactuating structure and because of the need for additional elements suchas stripper rings or an additional step in the machine cycle toaccommodate the air blow off of the article. Other designs havecontemplated a machine sequence wherein the blow article remains in theblow mold as the core is retracted. Thus, the closed blow mold acts tostrip the finished article from the core. However, in such designs theuse of partible neck rings which move only in a direction transverse tothe axis of the core have been suggested. These latter mentioned designsare disadvantageous from the view point of machine control and operatingspeed as, before the core can be retracted, the neck rings must becompletely opened to insure that no damage occurs to the neck of thearticle. In order for the neck rings to be opened, the clamping pressureof the press must first be relaxed to allow the neck rings to move. Thisresults in an increase in machine cycle time and control complexity.

With respect to blow mold actuation, several designs have been proposedwherein common actuating elements have been utilized to open a pluralityof blow molds. These designs use two corresponding mold halves, eachincluding a plurality of mating mold cavities. In such designs, the blowmolds must be arranged in a linear manner and thus are not adaptable todesigns employing annularly alternating blow molds and injection molds.Also, as previously set forth above, it has been known to employ blowmolds with divergently outwardly opening mold sections slideably mountedon inclined surfaces or supports. Such blow molds have been utilizedwith machines employing alternating blow mold and injection moldarrangements. However, commonly in these designs, the mold sections aremounted in cavities in one of the platens and are closed flush with thesurface of the platen. This in turn requires the use of an injectionpress capable of developing very high clamping force to maintainadequate closing pressure between mold parts because the mating contactarea between the platens is great, constituting substantially the entireface of each platen. This is disadvantageous for reasons mentioned belowand, in addition, this type of blow mold structure is expensive andcomplicates the problems of heat transfer from the mold.

In previous designs employing rotatable or oscillatable core carryingelements, the supply of various fluids, such as high pressure air andheat transfer mediums, has been accomplished by the use of flexiblehoses. A multiplicity of hoses are required to supply the fluids from astationary distribution point to a plurality of points of use on therotating core carrying element. This system of supply gives rise toproblems of fluid leakage as leaks are prone to occur in the hosecouplings and hoses as a result of constant flexing.

Previously, it has been known to mount core assemblies on relativelymovable platens of injection molding presses so that the neck ringoperating structure and base of the core are received in a cavity in oneof the platens. This has in part, been necessary because core assemblieswith attendant neck ring actuating structure are large, therebyprecluding the mounting of these assemblies on the surface of platensbecause of the restricted daylight opening between the injection pressplatens. Thus, the core mounting structure and neck ring actuatingstructure are recessed below the clamping surface of the platen andaccess to these parts can be accomplished only by removing the entirecore assembly. This unnecessarily complicates maintenance procedures andincreases the amount of time necessary to accomplish the change-over ofmold parts when a change in container shape is desired. Also, in thesedesigns the neck rings close flush with the face of the platen. Thisincreases the mating surface area between platens. It should be realizedthat in order to prevent leakage of the injected plastic materialbetween mating portions of the cores and injection cavities, it isnecessary to seal such portions at a pressure greater than the pressureof the injected plastic material. Therefore, the greater the surfacearea of such mating portions, the higher the clamping force of the pressplaten must be. Thus, machines utilizing such designs require injectionpresses capable of developing excessively high clamping forces. This isso because the pressure necessary to maintain a seal between the matingportions of the cores and injection cavities to overcome the pressure ofthe injected plastic material must be generated over substantially theentire face area of the mating platens.

It is an object of this invention to reduce the operating cycle time ofblow molding machinery by the use of improved neck ring and blow moldstructure.

It is an object of this invention to provide blow molding apparatuswherein the area of abutting surfaces of mating parts is minimized.

It is another object of this invention to utilize an operating sequenceof mold parts which takes maximum advantage of the basic operating cycleof an injection molding press to reduce machine cycle time.

It is an object of the invention to provide core assemblies of which themounting portion is of reduced dimension in a direction lengthwise ofthe core to allow mounting of the core assembly to an exterior surfaceof a platen without the need for increasing the daylight opening betweenrelatively movable platens of an injection press.

It is another object of this invention to provide improved blow moldactuating structure for opening and closing blow molds.

It is an additional object of this invention to provide blow moldingmachinery having improved fluid supply systems.

It is a further object of this invention to provide blow moldingapparatus including provisions for increased accessibility of moldparts.

It is also an object of this invention to provide blow mold apparatuswherein required platen clamp tonnages are reduced.

Briefly, these and other objects of the invention are achieved byutilizing divergently outwardly opening neck rings which move away fromthe neck of the formed article simultaneously with the withdrawal of thecore from the article. The finished article remains in the closed blowmold, thereby allowing an overlap in the core removal and coolingsegments of the machine operating cycle and allowing a shorter totalmachine operating cycle. The blow mold sections are openedsimultaneously by a common actuating structure which moves the moldsegments arcuately toward and away from each other. Core assembliesutilizing fluid motors formed integrally with parts of the core assemblyare of reduced length and allow mounting of the core assemblies onsurfaces of a core carrying element. Fluid supply systems formedintegrally in the core carrying element supply required fluids to thecore assemblies.

FIGS. 1 through 4 form a sequential diagrammatic illustration of themachine operating cycle of one type of injection blow molding machineusing mold parts in accordance with the present invention.

FIG. 5 is a sectional illustration of one form of core assembly whichmay be used in the equipment diagrammed in FIGS. 1 to 4 or alternatelyin other equipment as will appear.

FIG. 6 is a face view of the core assembly illustrated in FIG. 5, takenalong line 6--6 of FIG. 5.

FIG. 7 is a partial sectional view of a second form of core assembly,which may be used in the equipment diagrammed in FIGS. 1 to 4 oralternately in other equipment as will appear.

FIG. 8 is a face view of the lower half of core assembly shown in FIG.7, taken along line 8--8 of FIG. 7.

FIG. 9 is a sectional side elevation of a second type of injection blowmolding apparatus employing an oscillatable turntable and having moldparts in accordance with the present invention, the right hand portionof the view being taken along line 9--9 of FIG. 12 and the left handportion being taken along line 9a--9a of FIG. 10.

FIG. 10 is a frontal elevation of the molding apparatus shown in FIG. 9taken along line 10--10 of FIG. 9.

FIG. 11 is a detailed view of mold mounting rings utilized in theapparatus shown in FIG. 9 taken along line 12--12 of FIG. 9.

FIG. 12 is an elevational view of the apparatus shown in FIG. 9 takenalong line 12--12.

FIG. 13 is a partial sectional view of a third form of core assembly,which may be used in the equipment diagrammed in FIGS. 1 to 4 or theequipment illustrated in FIGS. 9 to 12.

FIG. 14 is a face view of the lower half of the core assembly shown inFIG. 13, taken along line 14--14 of FIG. 13.

There is shown in FIG. 1 a generalized view of injection blow moldingmachinery of the type disclosed in U.S. Pat. Nos. 3,339,231 and3,412,186, the disclosures of which are hereby incorporated byreference. Briefly, this apparatus is comprised by a fixed platen 20 onwhich is mounted a plurality of injection molds 22. Softened resinousplastic in a flowable state is supplied to the injection molds 22 by asuitable hot runner system (not shown) contained in the fixed platen 20.The softened material is supplied to the hot runner system by a feedsystem such as a screw-type feeder 24 which supplies plastic material toa nozzle 25.

Extending from the fixed platen 20 are parallel tie bars 26 on which areslidably mounted intermediate platen 27, and a movable platen 28. Theintermediate platen 27 carries a carriage 29, that is mounted foroscillation about an axis transverse to the direction of movement of theintermediate platen 27 on tie bars 26. Core assemblies C are mounted inaligned and opposed relationship on opposite sides of carriage 29. Thecore assemblies include a mounting base 31, neck ring parts 32 and apreform core element 33. The core assemblies C also include mounting andactuating structure for the neck ring parts 32 which shall behereinafter described with respect to FIGS. 5-8. Although, in theinterests of simplicity, the equipment herein schematically illustratedshows only one core assembly mounted on each side of the carriage 29, itshould be realized that in commercial form, a plurality of coreassemblies are mounted on the carriage 29.

The blow molds 34 are each comprised of blow mold halves 34a and 34b andthe blow molds are mounted on movable platen 28. In the diagrammaticillustrations of FIGS. 1-4, suitable actuators such as hydraulic motors35 urge the blow mold parts 34a and 34b toward and away from each otherto open and close the blow molds.

Means are provided in the apparatus shown in FIG. 1 for causing theintermediate platen 27 and movable platen 28 to be moved along the tiebars 26. Also, actuating structure is provided to cause carriage 29 tobe oscillated in an arc of 180°. Suitable structure for accomplishingthese functions is illustrated and described in the aforementioned U.S.Pat. Nos. 3,339,231 and 3,412,186.

Briefly, regarding the operation of the apparatus illustrated in FIGS.1-4, when the platens 27 and 28 are closed, i.e. positioned as shown inFIG. 1, opposed core elements 33 are received in injection mold 22 andblow mold 34. A preform A is formed on the core element and in the moldcavity of the associated neck rings 32 by the injection of plasticmaterial into the injection mold 22. Simultaneously, a preformpreviously formed on the opposed core element 33 is blown into shape ofthe finished article B in the blow mold 34. After the preform A andfinished article B are so formed, the platens 27 and 28 are separatedfrom fixed platen 20 and the carriage 29 is rotated 180°, therebytransferring preform A for insertion in a blow mold 34 and a free core33 for insertion in injection mold 22. The movable platens 27 and 28 arethereafter closed, i.e., moved to the right toward fixed platen 20 asshown in FIG. 1, and the moved recited forming steps are repeated. Adetailed description of machine operating cycle appears below.

A vacuum hold down and ejector device 36 is mounted in the bottom ofblow mold 34 for purposes to be hereinafter described.

Referring to FIGS. 5 and 6, there is shown one form of core assembly C.The core assembly is comprised of a mounting section 31, a pair of neckring parts 32a and 32b and a core element 33. The mounting section 31includes a core mounting block 40 on which is mounted the core element33. A pair of pins 42 are fixed on the core mounting block 40 and extendangularly outwardly with respect to the center line of core element 33.

The neck ring parts 32a and 32b are mounted for divergently outward andconvergently inward movement with respect to core element 33 by means ofneck ring mounting blocks 43 which are slidably mounted, as by means ofcylindrical bushings 44, on the pins 42. The bushing 44 forms afluid-tight seal with the exterior surfaces of the pin 42. For reasonsas will hereinafter be described, each pin 42 includes a longitudinalbore 45 extending the length of pin 42. Each neck ring part 32a and 32bis secured to a neck ring mounting block 43 by suitable fasteningelements such as machine screws 46. The mounting blocks 43 include agroove or channel 47 which terminates in an end wall 48. Heel blocks 50are secured to mounting base 40 adjacent the mounting blocks 43. Heelblocks 50 include an inclined surface 51 and a stop element 52 fixed onthe heel block 50, for instance, by a threaded fastener 54. The stopelement 52 is positioned to be engaged by the end wall 48 of channel 47formed in the neck ring mounting blocks 43, as will hereinafter bedescribed.

When the split neck ring parts 32a and 32b are in place adjacent thebase of core element 33, a neck mold cavity 32d is formed betweeninternal surfaces 32c of the neck rings and the corresponding portion ofthe core element 33. When the core element 33 is inserted in aninjection mold cavity, the neck ring parts 32a and 32b are in abutmentwith the top surfaces of the injection mold as shown in FIGS. 1 through4, and the neck mold cavity 32d forms a continuation of the preform moldcavity formed between core element 33 and the injection cavity of theinjection mold. When plastic material is fed under pressure into theinjection cavity, such material also enters the neck mold cavity 32d andforms therein the neck of the article being molded. When the neck of thearticle is formed with an irregular outer surface, as for instance, witha thread, it is necessary to separate the neck mold parts 32a, 32b fromthe neck of the formed article to enable axial retraction of the coreelement 33 from the article without damage to the neck of the article.

The core assembly C is mounted to a mounting member M, (FIG. 5), forinstance, the carriage 29 of the apparatus illustrated in FIG. 1 orturntable T of the apparatus illustrated in FIG. 9, by means offasteners 53 passing through the flange of the core mounting block 40.The core assembly C is mounted to the plate M so that the longitudinalchannels 45 in pins 42 are in fluid tight registry with conduits 56formed in mounting plate M. Also, conduits 57 and 58 formed in mountingblock 40 are in registry with conduits 59 and 59b respectively formed inmounting plate M. Further, air supply conduit 60 formed in mountingblock 40 is in registry with air supply conduit 61 formed in mountingplate M. Suitable seals, such as flexible O-rings, are disposed in themounting plate M and form a fluid tight seal at the interface betweenthe various aligned conduits. Also, stem S of the core element 33 isreceived in a suitable aperture 62 in the mounting member M and acentral tube 66 in the stem S communicates with internal passage 65formed in plate M for purposes of supplying a heat transfer medium tothe core element 33 as will hereinafter be described.

As the bushing 44 forms a fluid tight seal with the pin 42, theintroduction of pressurized fluid through channel 45 into the spacebetween the top of pin 42 and mounting block 93 will cause the mountingblock and bushing to be moved relative to pin 42. Because of the angularmounting of the pins 42, the neck ring mounting blocks 43 move upwardlyand outwardly with respect to the core element 33. Outward travel of theneck ring parts 32a and 32b is determined by the position of stopelement 52 with respect to the surface 48 carried by the neck ringmounting block. When the surface 48 is positioned against the stopelement 52, the neck ring parts will be at the maximum extent of travelas shown in the phantom lines of FIG. 5.

With reference to FIGS. 1 through 4, the operating cycle of one type ofinjection blow molding machine utilizing core assemblies as hereindisclosed is described. As previously stated, FIG. 1 depicts a point inthe operating cycle of the apparatus as disclosed in U.S. Pat. No.3,339,231. At the point shown, the movable platens 27 and 28 are closedand a preform A and a formed article B are simultaneously formed in theinjection mold 22 and blow mold 34, respectively. At the injectionstation 22, the neck mold parts 32a and 32b are closed about the base ofcore element 33 thereby defining a molding chamber for the formation ofthe neck of an article.

When the walls of the finished element B have been blown into contactwith the interior molding surfaces of the blow mold 34, the platen 28 ismoved away from the platen 27. Just prior to the separation of theplaten 28, the actuating structure for the neck mold parts 32a and 32bis supplied with fluid under pressure. When the platen 28 moves awayfrom the platen 27, the neck mold parts 32a and 32b are moved outwardlyby the previously decribed actuating structure and remain in engagementwith the faces of the blow mold parts 34a and 34b, as shown in FIG. 2.As the neck mold parts 32a and 32b move in the direction of travel ofthe platen 28, the mold parts, by reason of the mounting structureheretofore described, slide outwardly across the faces of the blow moldparts 34a and 34b, thereby moving away from engagement with the neck ofthe article B. It should be realized that the neck ring parts 32a and32b can begin opening immediately upon the beginning of movement ofplaten 28 as the clamping pressure between the faces of the blow moldparts 34a and 34b and the neck rings parts 32a and 32b will have beenterminated.

Referring to FIG. 3, as the platen 28 continues to move, the neck ringparts 32a and 32b will eventually reach a limit of travel as herebyforedescribed and platen 28 will continue to move away from platen 27. Also,the platen 27 will begin to move away from the fixed platen 20 toretract a core element 33 from an injection mold 22. At or near the timethe platen 28 reaches its open position, the blow mold parts 34a and 34bwill begin to separate. The finished article B will be held at itsbottom surface by the vacuum hold down and ejector device mentionedabove and hereinafter described in more detail with respect to the blowmold illustrated in FIG. 8. Once the blow mold halves have been fullyretracted, the vacuum holding the article B is terminated and theejector is actuated to propel the finished article from the opened blowmold. The carriage 29 is then turned through 180° and the platens 27 and28 are again closed to the position shown in FIG. 1. Closure of the neckring parts 32 a and 32b of the core entering the injection cavity 22 isaccomplished by the front face of the injection mold as the platen 27moves toward fixed platen 20.

Referring again to FIG. 5, cooling of the neck ring parts 32a and 32bcan be accomplished in the following manner. The underside of the coreelement 33 is provided with an annular channel 63 which, with suitableseals such as O-rings 64 forms, with the top of core mounting block 40,a fluid tight channel. Cold water or other suitable cooling medium isintroduced from conduit 59 in the mounting plate M to the channel 63 viaa water inlet channel 58. A second channel 57 similar to inlet channel58 serves as an outlet channel in a manner as previously described inconnection with conduit 58. Cold water supplied by conduit 58 circulatesthrough channel 63 and cools the lower portion of core element 33. Inretracted position, the neck ring mold parts 32a and 32b are positionedagainst the top side of the flange 49 of the core element 33 and heat isdrawn from these neck mold parts by conduction through the flange 49 andbase of core element.

Core element 33 also includes a second heat transfer circulation systemincluding a tube 66 which communicates with a source of heat transferfluid 55 in the mounting plate M. Fluid from the source 65 is carried upthrough the center of the stem S by the tube 66 to the barrel 67. Heattransfer fluid fountains from the barrel 67 beneath the top of the coreelement 33 then travels, via the annular space 68 between the barrelspace 67 and the core element 33 to a plurality of conduits 69 formed inthe stem S. The fluid from the conduit 69 empties into a collectionchamber 70 from which the heat transfer fluid is collected and conveyedelsewhere in the plate M.

Blowing air is supplied to core element 33 by a suitable supply conduit61 disposed in the mounting plate M which communicates with a conduit 60disposed in the core mounting block 40. In order to introduce blowingair to the interior of a preform, the core element 33 is comprised of amovable tip section 71 and a base section 72. The tip section 71includes an annular mounting section 73 slidably received on the reduceddiameter shoulder 76. Thus, the tip section 71 is mounted for movementrelative to base section 72. Such movement is limited, however, to atotal distance of about several thousandths of an inch by a stop member,such as a snap ring 75 disposed on the inner portion of the mountingsection 73. When air is introduced through conduit 60, it is received ina chamber 77 in the mounting section 72. A conduit 78 formed in themounting portion 72 and communicating with the chamber 77 carries theair to the outer surface of the mounting section 72, whereupon the tipsection 71 of the core element 33 is urged outwardly thereby forming anannular blowing orifice between the bottom edge of the tip section 71and the mounting section 72.

In FIGS. 7 and 8 there is shown a second embodiment of a core assemblyincluding a core element 80 and neck ring parts 81a and 81b. The overalllength L of the core assembly 80 is minimized by the use of the neckmold actuating arrangement wherein the primary direction of travel ofmotors separating the neck rings is normal to the longitudinal axis ofthe core element 80. As shown in FIG. 7, the core element 80 is mountedto a core mounting block 82 that includes a plurality of chambers orcores 83. Disposed in the cores 83 is motor means in the form of a fluidmotor with a piston element P having suitable sealing elements such asO-rings 84 engaging the surface of the chamber 83. In the embodimentdisclosed, the direction of travel of the piston P is normal to thelongitudinal axis of the core element 80, but it should be realized thatthe piston could be canted but still have a direction of travel whereinthe major component of movement is in a direction perpendicular to thelongitudinal axis of core element 80. Designs having the pistons Pcanted at angles of up to 45° have yielded desired results in terms ofoperation and compactness, as later described in connection with FIGS.13 and 14.

The piston P is moved outwardly of the chamber 83 by the introduction offluid under pressure through a conduit 85 into the space between theback wall 86 of the chamber 83 and the piston P. The face 87 of thepiston P slideably engages mounting block 88 to which neck mold sectionssuch as sections 81a and 81b are mounted. The neck ring mounting blocks88, when urged outwardly by the piston P, move upwardly on inclinedsurface 90 disposed on heel blocks 91.

Guides 92 are fixed to the heel block 91 to guide the mounting blocks 88laterally as they slide on inclined surface 90 of the heel blocks 91.Thus, when the piston P moves outwardly, the mounting blocks 88 arecaused to move outwardly and upwardly along the inclined surfaces 90,causing the neck ring sections, such as section 81a, to be moveddivergently outwardly from the core element 80 (as shown by the dottedlines in FIG. 7), thereby becoming free from the neck of the article Bdisposed on the core. The extent of travel of the neck rings is limitedby a projection 88a on the mounting block 88 which abuts the surface 91aof the heel block 9 when the neck rings have been opened the desireddistance.

In FIG. 13 there is shown a core assembly similar to core assembly Cpreviously discussed in connection with FIGS. 7 and 8. In the embodimentshown in FIG. 13, a core element 180 is mounted on a core mounting block182. The core mounting block has formed therein at least two chambers,such as chamber 183 in each of which is disposed a piston P havingsealing means 184. Each chamber 183 communicates with a source of fluidunder pressure through a conduit 185 formed in the core mounting block182. It should be noted that the longitudinal axis of piston P isdisposed at less than a 90° angle with respect to the longitudinal axisof the core element 180. In the preferred embodiment, the foregoingangle is about 45°.

Positioned outwardly of the core mounting block 182 are two heel blocks191, each having formed thereon an inclined surface 190. A neck moldsection mounting block 188 is slidably disposed on each surface 190 andhas mounted thereon one of the neck mold sections 181a and 181b. Theintroduction of fluid under pressure through conduit 185 into chamber183 causes the outward movement of the piston P which in turn moves neckmold section mounting blocks 188 on the inclined surfaces 190, therebycausing the neck mold sections 181a and 181b to move away from the neckof an article formed on the core element 180, as shown in the dottedline positions of FIG. 13. Lateral movement of neck mold sectionmounting blocks 188 is precluded by a pair of guide members 192positioned on each side of the neck mold section mounting blocks.

Because of the angular inclination of pistons P in the embodiment shownin FIG. 13, the lateral extent of the core assembly (the distancebetween the outside edges of top and bottom heel blocks 191 asillustrated in FIG. 13) can be reduced in comparison to the embodimentsillustrated in FIGS. 7 and 8. This allows the mounting of a greaternumber of such core assemblies on apparatus as heretofore described inFIG. 1 and as hereinafter described in FIGS. 9 through 12.

The supplying of coolant to the neck rings, of heat transfer fluid tothe core element, and of blowing air to the core assemblies shown inFIGS. 7 and 13 is accomplished in generally the same manner as thereheretofore described in connection with the core assembly shown in FIGS.5 and 6. Coolant is supplied via inlet conduits (not shown) to annularchannels 89 (FIG. 7) and 189 (FIG. 13), formed on the bottom surface ofcore elements 80 and 180, respectively. Suitable outlet channels (notshown) are provided to withdraw coolant from the channels 89 and 189.The coolant flows through the channels 89 and 189 and draws heat fromthe base of the core elements 80 and 180. Because the base of the coreelement is cooled, heat is drawn from the neck ring sections 81a and 81b(FIG. 7) and 181a and 181b (FIG. 13) by conduction when the neck ringsections are closed about the base of the core element. Thus, theplastic material which flows into the cavity formed between the coreelement and the neck ring sections is quickly solidified prior to theblowing step, thereby ensuring a good neck finish on the formed article.

In FIG. 9 there is shown another form of injection blow moldingapparatus. This type of apparatus is comprised of two sections E and F.The section E includes an annular array of preform injection molds andblow molds mounted in an alternating series. As shown in FIG. 9, thesection E is mounted to the fixed platen R of an injection press. Thesection F includes a plurality of core assemblies of the type previouslyillustrated in FIGS. 5-8, mounted on an oscillatable turntable T. Theturntable T is mounted for oscillation on the movable platen U of theinjection press.

In the apparatus shown in FIGS. 9 through 12, the movable platen U ismoved toward the fixed platen R to position the mold cores in the blowmolds in injection molds of the alternating mold arrangement mounted onthe fixed platen R. While the platens are closed, preforms are formed oncores disposed in the injection molds and finished articles are formedon the blow molds. When this segment of the cycle is complete, themovable platen U is moved to retract the cores from the molds and theturntable is oscillated by a suitable drive system, for instance, thehydraulic rack and gear drive system DS shown in FIG. 9, to position thecores in alignment with alternate injection molds and blow molds. Themovable platen U is then moved toward the platen R and the cores arere-inserted in the injection molds and blow molds.

Plastic material is caused to flow from the injection sprue 93 through asuitable hot runner system 93a to a delivery nozzle 93b from whence itis injected into the injection mold, thereby forming a preform A.

In the apparatus illustrated in FIGS. 9-12 the blow molds 95 and 96 arecomprised of partible sections 95a and 95b and 96a and 96b respectivelywhich are mounted for arcuate movement, as will herein later bedescribed, so that the blow molds 95 and 96 are alternately opened andclosed. Rotatable mounting elements such as mounting rings 98 an 99 arerotatably mounted on hollow center post 100 secured to mounting plate N,the centerpost 100 forming a pivot member defining a pivot axis. Asshown in FIG. 11, the mounting rings 98 and 99 form supports for themolds 95 and 96 and can include a generally annular body section such as98a and 99a from which projects a plurality of arms 98b and 99b. Itshould be realized that the number of arms projecting from the body isdetermined by the number of blow molds contained in the annular arrayand that such arms will be equiangularly spaced with respect to eachother. Each of the arms 98b and 99b includes a mounting lug 98c and 99cdisposed at its outer end. Corresponding blow mold parts such as 95a and96a and 96b are secured to the mounting lugs 98c and 99c respectively.

Actuating structure or means is provided to cause mounting rings orsupports 98 and 99 to be rotated or pivoted in opposite directions toeach other on the post or pivot member 100. One such actuating structureis illustrated in FIG. 10 and includes two hydraulic jacks 101 and 102mounted by trunnions 103 and 104 respectively to the mounting plate N.The drive rods of each hydraulic jacks 101, 102 are secured by suitablemeans, such as by a clevis 105 and 106 respectively to blow moldsections 95b and 96a respectively. When the jack 101 is actuated, theblow mold section 95b is urged toward the right as viewed in FIG. 10, tothe dotted line position there shown. It will be recalled that the blowmold section 95b is rotatably mounted to the post 100 by reason ofmounting ring 99 and therefore, the movement of blow mold half 95b isarcuate and in a counterclockwise direction. As the mounting 99 is movedby reason of movement of blow mold half 95b, all arms 99b on themounting ring 99 will be subject to the same arcuate movement as blowmold section 95b. Therefore, all blow mold sections affixed to themouting ring 99 will be moved an equal arcuate distance. In a likefashion, blow mold section 96a is moved in a clockwise direction by thehydraulic jack 102 thereby rotating mounting ring 98 and causing equalarcuate movement of all blow mold sections affixed to the mounting ring98. Thus, joint actuation of hydraulic jacks 101 and 102 causes each ofthe blow molds, such as molds 95 and 96 to be opened by arcuate movementof the respective blow mold halves in opposite directions as shown inthe phantom view of blow mold 95 in FIG. 10. Similarly, actuation ofhydraulic jacks 101 and 102 in directions opposite to that previouslydescribed causes arcuate movement of the blow mold sections to the fullline positions shown in FIG. 10, thereby closing the blow molds.

As shown in FIG. 9, the blow molds also include a combined vacuum holddown and ejector assembly 36 including a base plate 110 mounted on themounting plate N and an ejector 111 including a stem 112 and a head 113.Affixed to the stem 112 at the end opposite the head 113 is a suitableseal 114 slidable in and in fluid tight engagement with chamber 115.Conduit 116 supplies air under pressure to chamber 115 to move theejector 111 outwardly. Conduit 117 constitutes an exhaust or vacuum linefor the escape of air from cylinder 115. Conduit 118 communicates with avacuum source and with an annular channel 119 formed between the head113 of the ejector 111 and the base plate 110.

While the ejector-hold down assembly 36 is illustrated in connectionwith the blow molds depicted in the apparatus of FIGS. 9-12, it shouldbe realized that such units can be used with all types of partible blowmolds including those which part linearly as illustrated in theapparatus of FIGS. 1-4.

The ejector-hold down assemblies 36 operate in the following manner.When the preform A is blown into the shape of a finished container Bagainst the walls of a blow mold and is cooled sufficiently so that thewalls have sufficient rigidity to be self-sustaining, the blow moldhalves are parted to allow removal of the finished article from themold. Just prior to parting, a source of vacuum is supplied to theconduit 118 which in turn induces a vacuum in the channel 119, therebyholding the finished article B, by its bottom, against the base plate110 and head 113. As the blow mold sections part, the finished article Bis retained centered on the base plate 110 and is freed from thesurfaces of the blow mold cavity as the blow mold sections move awayfrom the finished article B. When the blow mold halves are opened to themaximum extent, high pressure air is supplied via conduit 116 to movethe plunger 36 outwardly of the chamber 115 thereby causing the finishedarticle B to be ejected from the blow mold. The extent of movement ofthe plunger 111 is in part dictated by the positioning of the partinglines of the blow molds. If all the blow molds part along a verticalparting line, as illustrated in the aforementioned U.S. Pat. Nos.3,339,231 and 3,412,186, then the finished articles B can fall, underthe influence of gravity, from the parted mold halves. In this instance,the plunger 111 is required to move only a short distance, on the orderof 1/4 of an inch, to dislodge the finished article B from the mountingbase 110. If the parting lines of the blow molds are other than verticalor if parts of the blow mold equipment are disposed so as to prevent thefree fall of the finished article from the opened blow molds, (as inFIG. 9 embodiment) then the ejector 111 must move a greater distance andmust propel the finished article beyond the longitudinal extent of theblow mold sections.

Certain aspects of the invention herein disclosed are concerned with thedistribution of fluid to the core assemblies on a rotating core carryingmount from a single point on the periphery of the rotating mount.Referring to FIGS. 9 and 12 a turntable T is mounted for oscillation onmovable platen U by means of a central shaft 120. As previouslydescribed, the drive system DS causes oscillation of the turntable T andshaft 120. Mounted to the turntable T are core assemblies C of the typeheretofore described with reference to FIGS. 5 through 8. A manifold 122is mounted in a recess on the rear surface of turntable 90. As shown,the manifold 122 can be annular in shape and includes two channels 123and 124 which, in conjunction with suitable sealing means 125, formfluid-tight passageways.

An input manifold 126 (FIG. 12) is disposed on a peripheral surface ofthe turntable T. The manifold 126 includes a plurality of fluidcouplings to which supply hoses are attached. As illustrated in FIG. 12,the input manifold 126 includes four connections 127, 128, 129, 130.

Cold water or other coolant for cooling the neck rings of the coreassemblies C can be supplied through orifice 127 to conduit 131 formedin the turntable 90. Conduit 131 communicates with annular channel 123and supplies cold water thereto. Conduits, such as conduit 59a areformed in the turntable T, for instance, by deep boring techniques, andconvey cold water from annular channel 123 to conduits such as conduit58 (FIG. 5) in the core assemblies C. As heretofore described the coldwater circulates through the core assembly C and is discharged to anoutlet 59b which communicates with the annular channel 124. The conduit132 formed in the turntable T conveys the discharged water from thechannel 24 to the water outlet 128. Thus cooling water for the neckrings of four core assemblies is supplied and carried away through onlytwo connections to the turntable.

Similarly, heat exchange fluid can be supplied through connections 130to conduits 65 which supply the heat transfer medium to the interior ofthe core assembly C as heretofore described. For simplicity only twoconduits 65 have been shown, but is should be realized that a conduit 65is necessary to connect each successive core. In instances where thenumber of cores is four or less, a plurality of conduits 65 can seriallyconnect all the cores so that heat transfer medium supplied throughorifice 130 can be discharged through connection 129 which communicateswith the last core in the series. However, if more than four cores areused, it has been found to be advantageous to use two or more separatecircuits for the heat transfer medium. Such additional circuits can besupplied from passages formed in the input manifold 126.

It will be recalled that turntable T is rotated when the platen U iswithdrawn from the fixed platen R after retracting the cores from theinjection molds and blow molds on the mounting plate N. To insure properalignment of the mold cores with the blow molds and injection molds oncethe turntable is oscillated, means must be employed to insure alignmentso that no damage occurs to the mold parts when the platens are onceagain brought together. In the apparatus disclosed in FIGS. 9 through12, this is accomplished by the use of a shaft 120 which includes aforwardly projecting extension 142 which, when the platens close, entersthe interior space 143 of the post 100. The extension 142 preventsengagement of the core assemblies C with the injection molds 94 and blowmolds 95, when the turntable T is not centered with respect to themounting plate N. Radial alignment of the core assemblies with the blowmolds and injections molds is accomplished by the use of a forwardlyprojecting pin which can be mounted on the mounting plate N. Theturntable T will then have mounted thereon locating blocks 141. When theplaten U is moved toward the fixed platen R, the pin 140 will engage oneof the locating blocks 141 to insure proper radial alignment of the moldcores and molds. If the radial alignment is improper, the tip of thelocating pin 140 will engage turntable T or parts of the core assembliesC mounted thereon and a suitable sensing circuit (not shown) will beenergized to prevent further movement of the movable platen U.

From the foregoing, it can be seen that an improved injection blowmolding apparatus has been provided which provides for a systemutilizing to maximum advantage the operating cycle of a standardinjection press, which provides only limited face-to-face contactbetween core assemblies and molds, and which provides core assemblieswhich are easily mounted on and removed from a supporting surface.

We claim:
 1. A mold assembly comprising a pivot member defining a pivotaxis, a pair of supports mounted on said pivot member in crossingrelation for individual pivoting about said pivot axis, at least twomolds with said molds being disposed on opposite sides of said pivotaxis, each of said molds being of a split construction and including twoparts, one part of each of said molds being mounted on each of saidsupports for cooperation with one another to define a closed mold andfor movement with said supports away from one another to define an openmold, and actuator means coupled to said supports for oscillating saidsupports and said mold parts about said pivot axis for simultaneousmovement of each pair of said mold parts between a mold opening positionand a mold closing position.
 2. A mold assembly according to claim 1wherein said pivot member is fixed and defines a fixed pivot axis.
 3. Amold assembly according to claim 1 wherein each mold includes a cavityhaving an axis disposed substantially parallel to said pivot axis.
 4. Amold according to claim 1 wherein said mounting means mount both of saidsupports for pivoting about said pivot axis, and said actuator means arecoupled to both of said supports for oscillating said supports inopposite directions.
 5. A mold assembly according to claim 4 whereineach mold includes a cavity having an axis disposed substantiallyparallel to said pivot axis.
 6. A mold assembly according to claim 4wherein said actuator means includes a separate actuator connected toeach of said supports for pivoting said supports in unison.
 7. A moldassembly according to claim 6 wherein said actuators are of theextensible fluid motor type.
 8. A mold assembly according to claim 6wherein said actuators are of the extensible fluid motor type with eachfluid motor being connected to a respective mold part.
 9. A moldassembly according to claim 6 wherein said actuators are of theextensible fluid motor type, said fluid motors being arranged generallyin parallel relation and in like orientation.
 10. A mold assemblyaccording to claim 9 wherein each fluid motor is connected to arespective mold part.
 11. A mold assembly according to claim 6 whereinsaid actuators are of the linear movement type and are arrangedgenerally in parallel relation and in like orientation.